reply to post by PlausibleDeniability
ok ok ... looks like I need to do damage control on rotary bashing. First, let me say, I have owned big blocks, small blocks, 4 cyl, 6 cyl ... and
of course rotaries.
well, did you know, they designed a Vette one time with a rotary engine? Rotary Corvette Prototype
'73 more on rotary
Or ... how about the DeLorean? what the
DeLorean should have had - not a flux capacitor
I understand the ignorance, and, since we are in BTS, I will let it slide.
The mention of the oil loss. Let me clear this up first. The way Mazda designed the engine is as such ... oil is INJECTED into the engine in small
quantities to LUBRICATE the apex seals. Of course, in this method, it uses it up. This system is run by an air pump, the higher the revs, the more
oil pumped for more lubrication. Thus, it could burn a quart over 3000 miles driven slow, or burn a quart in 500 miles if you drag race from light to
light or drive at 7000 rpms (yes, some people try not to drop below 3000 rpms in daily driving).
The problem is ... if people don't follow manufacturer's maintenance ... there could be a problem ... that isn't Mazda's fault. Keep it with
oil, keep the oil clean. A VERY important part is the cooling system. The engine runs hotter than a piston engine. What that image below doesn't
show you is all of the cooling tubes that flow around the outside of the chamber. IF you allow your cooling system to fail, or don't keep up on
maintenance (changing fluid, etc.) then, of course, it will overheat ... overheating will cause metal to change shape ... it will also cause the
fuel to pre-detonate ... when the fuel explodes before it is suppose to, THIS can tear up apex seals.
Over the years, Mazda increased the apex seals width, experimented with different materials. People who heavily modify their engines have the rotors
changed to accept 3 mm seals and use ceramic.
A stock rotary motor in the 2nd generation platform put out approximately 150 hp, the turbo about 185 hp ... out of a 1.3 L engine that could rev to
about 8000 rpms. a in 89-91, it was increased to 200 hp for the turbo and about 165 hp for the non-turbo. In 93, the sequential twin-turbo raised it
to 250 hp, but a drastic rise in available torque makes it a powerful beast on the road ... since RX-7s (and 8s) are known for their near 50/50
weight distribution and weight around 3000 lbs.
BTW, a RUNNING rotary can weigh as little as 150 lbs ... so power to weight of the engine SLAUGHTERS a LS1 engine ... so does the hp to cid. Very
few people actually put V8s in the chassis, and it is highly frowned upon by most owners of the vehicle ... a major reason, it throws off the
handling and balance of the car with all that extra weight.
The thing about a rotary, it has a lot of untapped power. If you put a full true dual exhaust (one pipe for each rotor from engine back at around
2-2.5" id) you will gain a large hp boost. If you want more, you will have to port the engine, since, stock ports are restrictive ... for best
streetability, go for a street port ... bridge ports and j-ports are larger, but it roughens the idle, so more suitable for racing. To free up
currently available horsepower, get a lighter flywheel, lighter rim and tire package ... you can even buy lighter rotors.
Since the RX-7 and RX-8 have a 50/50 weight balance, they drive fine in the snow ... they don't push/plow. With any rear drive vehicle, it depends
on the control of your foot on the gas pedal. What the poster before did is try to manipulate perception. That LS1 is just as hard to drive in the
rain or snow. I know, I drove a 70 Monte Carlo with a drag modded 454 in it which got about 5 mpg. All three of my rotaries got between 17-28 mpg
... depending on how I drove them. My 75 Pontiac Grand Ville convertible with a 400 got 9 mpg. My 76 nova with a 350 got between 10-15 mpg. my
dads 79 El Camino with a 350 got about 8-12 mpg (gearing on that one).
I have driven many vehicles with many different engines. I have studied my own cars a lot, for I was always passionate about them. I plan on owning
another Grand Ville as well as another RX-7.
I am giving you NON-BIASED info and opinions.
btw that 787B LeMans 4-rotor ... won its first year ... they banned rotaries or heavily restricted them in races since ... I thought about racing
one, but there are weight and class restrictions that murder your ability to compete ... putting your 1.3L with a weight penalty against a BMW just
doesn't seem fair ... rules may have changed since, but that was 5-10 years ago.
I will give you one hint, and this goes for any car. The faster you drive, the more gas you burn. The numbers advertised are highway mileage. I
drive a Hybrid now, and, if I gun it from red light to red light in the city, I will get in the mid-30s in mpg. If I drive defensively and
respectfully I get in the mid 40s to mid-50s in the city. If I drive like a 'grandpa' I can get over 60 mpg in the city on full tanks repeatedly.
I have also gotten close to 90 mpg on the interstate going from texas to florida. It is all in foot control ... using the least amount of gas pedal
to accelerate and maintain speed, maximize costing, timing red lights to conserve momentum ... that is what saves more fuel than anything. If you
foot is always on the gas or brake ... you mileage suffers.
If you want any tips on driving economically or want me to hunt down my old rotary links, feel free to U2U me. I know more about those two things
than I have use for.
The RX-8 is nice. I wanted to buy one and put a supercharger on it ... though the smooth revving of a naturally aspirated rotary is something else.
Just don't over-rev it. The reason is, the eccentric shaft is designed for a certain load. As you increase the speed, the force of the weight of
the rotors increases. It is hardened for a certain rpm range in mind. I think the RX-8 is 9 or 10k. This is the highest for a rotary production. I
believe the 89-91 non-turbo was 8500 rpm.